Steel rail.



I M mar/WM? R. A. LEWIS, w. R. SHIMER & w.1. THOMAS.

S- EEEEEEE L.

I APPLICATION FILED MAY 15. !95. 1 ,285 ,749. Patented Nov. 26, 1918.

STEEL RAIL.

" To all whom it may concern:

Be it known that we, Roy A. Lnwrs, WIL- LIAM ROBERT SHIMER, and WILLIAMJ. THOMAS, all citizens of the United States, and residents ofBethlehem, Northampton county, Pennsylvania, have jointly invented newand useful Improvements in Steel Balls, of which the following is aspecification, reference being had to the accompanying drawings, inwhich The figure of the drawing shows .a sectlon of a rail illustratingthe microstructure of a rail embodying our invention, magnified 100diameters.

Our invention relates to steel rails, and

consists particularly in a rail containing less than .90% carbon, 1.00%manganese, and with silicon, sulfur and phosphorus in the percentagesusually found in open hearth rail steel, and having a high tensilestrength,

a high elastic limit, an elongation, a reduc-v tlon in area, and ahardness under the Brinell'tests much greater than is found in anuntreated rail of the same composition.

Typical examples of rails embodying our invention, containing, (1) .61%'carbon, '.68'% manganese; (2) .71%' carbon, .76% manganese, and withsilicon, sulfur and phosphorus in the percentages usually found in railsteel, treated in accordance with our have given the following resultsin comparison with untreated rails of the same composition:

7 (1.) .61% carbon, .68% manganese.

s Treated. Untreated.

Tensile stren hpers in 130 000 lbs.- 107 500 lbs. Elastic limit if sq.ni 801 000 541000 Elongation 17.5% 15.0 Reduction in area 43. 3% 24. 08%Brinell hardness No 245 214 (2.) .71 carbon, .7675 manganese.

V Treated. Untreated. Tensile strength per sq. in 138, 000 lbs. 120,000lbs. Elastic limit per sq. in 88,000 66,000 Elongation 19. 5% 13.5%Reduction in area 48. 8% 22. 3% Brinell hardness No 260 227Specification of Letters Patent. Application filed May 15, 1915. SerialNo. 28,282.

Patented Nov. 26, 1918.

the treated steel showing the following increases over the untreatedsteel:

S eoimen lie. 1.

Specimen N o. 2.

. Tensile strength per sq. in Elastic limit per sq. in ElongationReductionin area Brinell hardness In both instances the treated steelshows much greater strength and higher elastic limit, and is much moreductile, although coniiderably harder, than the untreated stee Untreatedspecimen No. 1, an 80-pound rail, supported on anvils spaced 3 feetapart, under a 2,000-pound weight, falling from a height of eighteenfeet, stood four blows be fore breaking, and the total deflection, measured from the points of support, was 5.90 inches, the total elongation(in six inches taken along the exterior of the deflected portion oftherail) was 1.31 inches, and the fracture was coarse and crystalline.

Treated specimen No. 1, of-the same section and mounted in the sameway-as the untreated specimen, stood six blows before breaking, with atotal deflection of 8 inches, and a total elongation (in six inchestaken along the exterior of the deflected portion of the rail) of 1.77inches. The fracture was fine and fibrous.

Untreated" specimen No. 2, a 100-pound rail, supported on anvils s need3 feet apart, under a 2,000-pound weig t, falling from a height oftwenty-three feet, stood four blows before breaking, and the totaldeflection, measured from the points of support, was 7 inches, the totalelongation (in six inches taken along the exterior of the deflectedportion ofthe rail) was .71 inches, and the fracture was coarse andcrystalline.

Treated specimen No. 2, of the same section and mounted in the same wayas the untreated specimen, stood seven blows without breaking, furtherblows being impossile on account of the limitation of testing machine,the total deflection was 11 inches, and a total elongation (in sixinches taken along the exterior of the deflected portion of the rail) of1.06 inches. It. was subsequently fractured and the fracture was foundto be fine and fibrous.

\Ve prefer to produce a rail having the characteristics above described,by taking a rail as it comes from the finishing rolls and the hot saw,cooling it in an air spray to a temperature well below the criticalpoint, and thereafter re-heating the rail to a temperature above thecritical point, and preferably between 1100 and 1500 F. When the railhas been heated so that all of its parts are of uniform temperature, wethen remove it from the furnace and introduce it into a bath of oil orother cooling medium, so as to cool it very quickly, and therebypreserve as much as is possible the solid solution of iron and carbon inwhich condition the rail is when heated to above the calescence point.The rail is cooled to between 500 and 1000 F., and is then introducedinto an annealing furnace, in which it is heated to between 1000 and1250 F., and is retained in the annealing furn'ace until all of itsparts have reached. a uniform temperature. It is then withdrawn andallowed to cool.

The completed rail has a microstructure of fine, granular pearlite andis almost free from free ferrite. The free ferrite found in the rail isuniformly disseminated in small particles throughout its section, as isshown in the figure of the drawings. It contains between .60%.90%carbon, .50%1.00% manganese, and sulfur, silicon and phosphorus in thepercentages usually contained in rail steel. It has a tensile strengthof approximately between 115,000 155,000 lbs. per square inch; anelastic limit of approximately between 70,000 and 95,000 lbs. per squareinch; an elongation of approximately between 15%25% (in 2 inches): areduction in area of approximately between 30%55%, and a hardness Copiesof this patent may be obtained for five cents each, by addressing the bythe Brinell test of approximately between 225 and 325.

Rails made in accordance with our invention are found not only to have agreater tensile strength and elastic limit than untreated rails of thesame composition, but they also have a much greater ductility andhardness, thus greatly increasing the life of the rail when made inaccordance with our invention.

The terms and expressions which we have employed are used as terms ofdescription and not of limitation, tention, in the use of such terms andexpressions, of excluding any equivalent for the features which we havedescribed, but recognize that various modifications are possible withinthe scope of the invention claimed.

What we claim is:

1. A steel rail having a microstructure of fine granular pearlite, andbeing almost free from free ferrite, containing approximately between.60% to .90% carbon, .50% to 1.00% manganese, and with sulfur, siliconand phosphorus in the usual percentages found inopen hearth rail steel,and having a tensile strength of over 115,000 lbs. per square inch, anelastic limit of over 70,000 lbs. per square inch, an elongation of over15%, a reduction in area. of over 30%, and a hardness by the Brinelltest of over 225.

2. A steel rail containing approximately between .60%.90% carbon,.50%1.00% manganese, and sulfur, silicon and phosphorus in the usualpercentages found in open hearth rail steel, and having a tensilestrength of approximately, between 115,000 and 155,000 lbs. per squareinch, an elastic limit of approximately between 70,000 and 95,000 lbs.per square inch, an elongation of approximately between 15% and 25%, areduction in area of approximately between 30% and and a hardness by theBrinell test of approximately between 225 and 325.

' BOY A. LEWIS.

W. ROBERT SHIMER. WILLIAM J THOMAS.

Commissioner of Batents,

Washington, 20. G,

and we have no in;

